[waterphone]

The assets in your 401k (if invested in the market, especially if invested in broad market index funds to be highly diversified) actually have value beyond simply being a speculative asset. They're shares in businesses with a lot of motivations to make a profit, and they're going to continue doing their best to do so, and you benefit from that as a shareholder.

Cryptocurrency is largely a bubble of speculation and get-rich-quick hype with not much actual utility for most people beyond a lot of claims that don't ever really pan out.